Oligomerization of the UapA purine transporter Is critical for ER-exit, plasma membrane localization and turnover
| Autor: | James Leung, Bernadette Byrne, George Diallinas, Olga Martzoukou, Mayia Karachaliou, Vassilis Yalelis, Sotiris Amillis |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Biochemistry & Molecular Biology
Green Fluorescent Proteins Biology Endocytosis Endoplasmic Reticulum Aspergillus nidulans Cell membrane Fungal Proteins Bimolecular fluorescence complementation Bacterial Proteins Structural Biology trafficking medicine Molecular Biology COPII Biochemistry And Cell Biology Science & Technology Membrane transport protein membrane sorting Endoplasmic reticulum Cell Membrane Membrane Transport Proteins Transmembrane protein Cell biology Transport protein Protein Structure Tertiary Luminescent Proteins Protein Transport medicine.anatomical_structure transport biology.protein COP-Coated Vesicles Protein Multimerization Life Sciences & Biomedicine bimolecular fluorescence |
| Popis: | Central to the process of transmembrane cargo trafficking is the successful folding and exit from the ER (endoplasmic reticulum) through packaging in COPII vesicles. Here, we use the UapA purine transporter of Aspergillus nidulans to investigate the role of cargo oligomerization in membrane trafficking. We show that UapA oligomerizes (at least dimerizes) and that oligomerization persists upon UapA endocytosis and vacuolar sorting. Using a validated bimolecular fluorescence complementation assay, we provide evidence that a UapA oligomerization is associated with ER-exit and turnover, as ER-retained mutants due to either modification of a Tyr-based N-terminal motif or partial misfolding physically associate but do not associate properly. Co-expression of ER-retained mutants with wild-type UapA leads to in trans plasma membrane localization of the former, confirming that oligomerization initiates in the ER. Genetic suppression of an N-terminal mutation in the Tyr motif and mutational analysis suggest that transmembrane α-helix 7 affects the oligomerization interface. Our results reveal that transporter oligomerization is essential for membrane trafficking and turnover and is a common theme in fungi and mammalian cells. |
| Databáze: | OpenAIRE |
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